1. Field of the Invention
The present invention relates generally to portable video player technology and the processing of video images and, more particularly, to techniques for deinterlacing and enhancing video images.
2. Description of the Related Art
There has been a rapid evolution from analog video technology to digital video technology because of the advantages that digital video has to offer. Digital video can be stored and distributed more cheaply than analog video because digital video can be stored on randomly accessible media such as magnetic disc drives (hard disks) and optical disc media known as compact discs (CDs). Once stored on a randomly accessible media, digital video may become interactive, allowing it to be used in games, catalogs, training, education, and other applications.
One of the newest products to be based on digital video technology is the digital video disc, sometimes called “digital versatile disc” or simply “DVD.” These discs are the size of an audio CD, yet hold up to 17 billion bytes of data, 26 times the data on an audio CD. DVD storage capacity (17 Gbyte) is much higher than CD-ROM (600 Mbyte) and a DVD can deliver the data at a higher rate than CD-ROM. Therefore, DVD technology represents a tremendous improvement in video and audio quality over traditional systems such as televisions, VCRs and CD-ROM.
However, a major problem in utilizing DVD and other digital video technology to display motion pictures is that is that the sources of motion pictures come at different frame speeds. For example, standard film is shot at a rate of 24 Hz while a television broadcast using the National Television System Committee (NTSC) standard updates motion at 60 Hz. Converting the motion picture into digital video through a process called deinterlacing often produces a noticeable reduction in resolution as well as distortions known as motion artifacts.
Another problem with utilizing digital video technology is that motion pictures come in various formats. For example, movies in the theater are formatted for a wide screen while video displays are often much narrower. Video image scaling converts a digital or digitized image from one format to another. For example, a digital image with a spatial resolution of 720 horizontal by 480 vertical pixels may have to be converted to another resolution in order to be displayed on a particular display device such as a LCD panel with a fixed resolution of 640×480. However, most prior art video scaling methods provide poor resolution in the converted image. The scaling methods that provide quality resolution are extremely expensive to implement.
Yet another problem with video image scaling is that it may require the transfer of data between two asynchronous and/or different data rate domains. Using the example in the above paragraph, scaling from 720 horizontal pixels to 640 pixels (9:8 ratio) requires an interface between a 54 Mhz domain and a 48 Mhz domain (9:8 ratio). In the prior art, the transferring of data between two asynchronous and/or different data rate domains used large, expensive buffers.
Another reason that digital video technology has been difficult to utilize is because DVD players are typically large, cumbersome devices that are difficult to transport. Because DVD players must be operationally attached to a video display, such as a television or television monitor, they are virtually impossible to use anywhere space is limited. Furthermore, prior art mobile video systems suffer from a large number of annoying problems. Hand-held and mobile television sets typically exhibit reception maladies such as RF multipath interference and poor or erratic signal strength in rural areas. Integrated TV/VCR combo units can counter these problems by providing tape playback capability, but they tend to be physically large and not truly portable.
In view of the foregoing, it is desirable to have a portable video player capable of being easily transported and being used under a wide variety of conditions. It is further desirable to have a method and apparatus of deinterlacing and reformatting that provides for preservation of the full resolution of an image, while at the same time eliminating motion artifacts. It is further desirable to have a method and apparatus for providing high quality video scaling and vertical processing while minimizing cost. It is desirable to have a method and apparatus that provides for an asynchronous data interface while minimizing cost and eliminating the need for large and expensive buffers.